Fix unsubscribe test for stores

In the unsubscribe test the promise is being  rejeced
and the error (from assert.fail()) is never caught by
Mocha. For this reason the test is always successful, even when
commenting out the unsubscribe call.
Make use of isFase instead of equal
Merge pull request #11 from bripkens/broken-test

Fix unsubscribe test for stores